Internally Ventilated Brake Disk for Disk Brakes

ABSTRACT

The invention relates to an internally ventilated brake disk for disk brakes, in particular for motor vehicles, having two friction disks that are arranged adjacent to one another, that are connected to one another by webs that have an essentially radial, preset curvature, and that form cooling channels between them for cooling air, and that are separated from one another in the peripheral direction. According to the invention, the webs ( 16 ) in each case extend along a preset curve section of a web curve ( 17 ) that has a preset curvature, with the individual web curves ( 17 ), separated from one another in the peripheral direction and extending between an outer peripheral edge ( 10   b ) and an inner peripheral edge ( 10   a ), have an essentially identical design.

The invention relates to an internally ventilated brake disk for diskbrakes, in particular for motor vehicles.

BACKGROUND OF THE INVENTION

EP 1 445 507 B1, in which multiple webs of different chord lengthsbetween two friction disks that are axially separated from one anotherdelimit essentially radial cooling ducts, shows such an internallyventilated brake disk. The shape of the webs and their arrangementdetermine decisively the specific throughput in cooling air or theachievable cooling capacity as well as the necessary rigidity andstrength of the brake disk.

The object of the invention is to propose a brake disk of the generictype that is further optimized virtually without additional expense withrespect to the achievable cooling capacity.

SUMMARY OF THE INVENTION

According to the invention, the webs extend in each case along a presetcurve section of a web curve that has a preset curvature, whereby theindividual web curves that extend separated from one another in theperipheral direction and in particular between an outer peripheral edgeand an inner peripheral edge of the brake disk or the friction disks ineach case have an essentially identical design or curve geometry; inparticular, the web curves have an S-shaped curvature geometry and/orare arranged equidistant from one another viewed in the brake disk'speripheral direction. As a result, in the case of simple manufacturing,a brake disk, in particular an internally ventilated brake disk for diskbrakes that allows for an excellent cooling capacity of the brake disk,can be designed. In this case, the design expense as well as themanufacturing expense for the webs along the respective web curvesections can be advantageously reduced by the identical web curvegeometry.

In particular, it can be provided in such a way that at least one partof the individual web extends along different curve sections; inparticular, the webs can be divided into webs that vary with respect totheir length of extension and/or their curve section in order to form acooling capacity of an internally ventilated brake disk that can bematched in an excellent and individual manner to the respectiveconditions. In particular, this is achieved by forming three differentgroups of webs, the primary webs, secondary webs, and tertiary webs,which in each case have a different length.

According to a preferred constructive embodiment of the invention, it isproposed to design longer primary webs, which are guided to the innerperipheral edge of the friction disks, but end before their outerperipheral edge, with, in contrast, the shorter secondary webs, viewedin the radial direction, being arranged approximately in the middlerelative to the friction disks and ending before the inner peripheraledge and the outer peripheral edge of the brake disk. Further, withregard to the secondary webs, shorter tertiary webs can also be providedthat preferably end approximately in the middle relative to the frictiondisks, viewed on the outer peripheral edge of the friction disks and inthe radial direction. As empirical tests have also shown, it is possiblewith these measures to further improve the specific throughput incooling air or the cooling capacity of the brake disk to a notinconsiderable extent, with the number of webs or the manufacturingexpense of the brake disk remaining virtually the same.

Advantageously, five webs that consist of secondary webs and tertiarywebs can be arranged alternating between each two primary webs; inparticular in this case, each two secondary webs can be arranged betweenthree tertiary webs. This produces an especially rigid and sturdyembodiment of the brake disk even in the case of high brake forces andtemperatures, on the one hand, and a flow-promoting equalization of theinflow cross-sections on the inner periphery and the dischargecross-sections on the outer periphery of the brake disk, on the otherhand.

Extensive-optimization of the cooling properties and the strengthcriteria of the brake disk can be achieved when the extension length ofthe primary webs has a negative (in the direction of rotation of thebrake disk) curvature section and a positive (opposite to the directionof rotation of the brake disk) curvature section, while the secondarywebs and the tertiary webs are designed only positively curved. In thiscase, the points of inflection of the curvature sections of the primarywebs and the radial ends of the secondary webs can lie essentially on acommon circular line.

In addition, the radial inner ends of the tertiary webs can be extendedout via the force application radius that lies approximately in thecenter of the friction disks, and the radial outer ends of the secondarywebs lie essentially on a circular path that also includes the radialouter ends of the primary webs and that is situated by a distance of atleast one web's width from the outer periphery of the brake disk.

To optimize the cooling capacity of the brake disk further, the angle ofthe primary webs on the inner peripheral edge of the brake disk can bebetween 0 and 20 degrees, in particular between 12 degrees to 17degrees, relative to a tangential beam that is applied through this areastarting from the brake disk center. Also, the angle of the tertiarywebs guided to the outer peripheral edge of the brake disk can bebetween 0 and 30 degrees, in particular between 10 and 22 degrees,relative to a tangential beam that is applied through this area from thebrake disk center. Finally, the curvature radius of the radial, outer,positive curvature sections of the primary webs that are inclinedopposite to the direction of rotation of the brake disks in, e.g.,forward travel, and the curvature radius of the secondary webs and thetertiary webs can be made the same.

BRIEF DESCRIPTION OF THE DRAWING

The diagrammatic drawing shows a partial cross-section through the websof an internally ventilated brake disk for motor vehicles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The drawing shows a segment of an internally ventilated brake disk 10for motor vehicles, of which, however, essentially only one annularfriction disk 12 can be seen. The second, axially adjacent frictiondisk. 14 is indicated diagrammatically only on the right edge of thedrawing.

The two friction disks 12, 14 of the brake disk 10 are connected to oneanother by means of webs 16, with essentially radial cooling channels(without reference numbers) being delimited between the webs 16. Thecooling channels extend in each case from the inner peripheral edge 10 ato the outer peripheral edge 10 b of the brake disk 10.

Also, on the inner peripheral edge 10 a of the brake disk 10, fasteninglugs 10 c are molded on, lugs in which holes are made via which thebrake disk 10 can be fastened to a wheel flange, not shown, of a wheelsuspension of a motor vehicle.

The webs 16 of the brake disk 10 are distributed in a symmetricalarrangement over the entire periphery thereof. Differently designedprimary webs 16 a, secondary webs 16 b, and tertiary webs 16 c extendalong a preset curve section of a web curve 17 (indicated in dots anddashes), which has here an approximately S-shaped curve geometry. Ineach case, the web curves 17 have an identical curve shape, and,moreover, preferably viewed in the peripheral direction, are alsoequidistant from one another.

The longer primary webs 16 a extend, as can be seen from the drawing,along a preset curve section of the respectively associated web curve 17up to the inner peripheral edge 10 a of the brake disk 10, but they endhere at a distance of approximately the primary web width in front ofthe outer peripheral edge 10 b of the brake disk 10.

The primary webs 16 a, which undergo transition into the fastening lugs10 c in each case on the inner peripheral edge 10 a, also have acurvature section with a negative curvature radius r₁ (curved in thedirection of rotation 24) and a radial outer curvature section with apositive curvature radius r₂ (curved opposite to the direction ofrotation 24), which undergo-transition into one another at a point ofinflection 18. The points of inflection 18 of the primary webs 16 a inthis case lie on a common circular path 18 a of the brake disk 10 aroundtheir disk center 19.

Between each two primary webs 16 a, three tertiary webs 16 c and twosecondary webs 16 b are arranged at the same peripheral distances, withtwo tertiary webs 16 c being directly adjacent in each case to theprimary webs 16 a, as can be seen.

The tertiary webs 16 c extend from the outer peripheral edge 10 b of thebrake disk 10 radially inward and end approximately at the center of thefriction disks 12, 14, whereby they extend beyond the dynamic forceapplication radius (circular line 20 indicated in dots and dashes),however.

The shorter secondary webs 16 b that are arranged in each case betweenthe tertiary webs 16 c are arranged approximately in the center of thefriction disks 12, 14 and symmetrically to the circular line 20, andthey end, as can be seen from the drawing, in front of the innerperipheral edge 10 a and the outer peripheral edge 10 bb of the brakedisk 10 at a distance that roughly corresponds to their web's width. Inaddition, the secondary webs 16 b end radially inward, for example, inthe area of the circular line 18 a of the points of inflection 18 of theprimary webs 16 b and radially outward on a circular path 22 alsoincluding the ends of the primary webs 16 a.

The webs 16 preferably have essentially a uniform web's width. Inaddition, the secondary webs 16 b and the tertiary webs 16 c areembodied with the same, positive curvature radius r₂, as is the case inthe radial outer curvature section r₂ of the primary webs 16 a.

In this case, the primary webs 16 a are on the inner peripheral edge 10a of the brake disk 10 and thus the radial inner web curve sections areinclined as a tangential beam 26 a relative to a straight line runningthrough the center of the circle 19 and the radial inner web curvesection, such that said webs form between them an angle of between 0 and20 degrees, in particular about 15 degrees.

Furthermore, the angle β of the radial outer tertiary web end sectionsof the tertiary webs 16 c that are guided to the outer peripheral edge10 b of the brake disk 10 relative to a straight line that is appliedthrough the center of the circle 19 and the radial outer tertiary webend section as a tangential beam 26 b is preferably between 0 and 30degrees, in particular about 20 degrees.

1. An internally ventilated brake disk for disk brakes, in particularfor motor vehicles, having two friction disks that are arranged adjacentto one another, that are connected to one another by webs that have anessentially radial, preset curvature, and that form cooling channelsbetween them for cooling air, and that are separated from one another inthe peripheral direction, wherein the webs in each case extend along apreset curve section of a web curve that has a preset curvature, withthe individual web curves, separated from one another in the peripheraldirection and extending between an outer peripheral edge and an innerperipheral edge, having an essentially identical design.
 2. The brakedisk according to claim 1 wherein the web curves have one of an S-shapedcurvature geometry and an arrangement equidistant from one another inthe brake disk's peripheral direction.
 3. The brake disk according toclaim 1, wherein at least some of the individual webs relative to theother webs extends along different curve sections of the respectivelyassociated web curve.
 4. The brake disk according to claim 3 wherein thewebs are divided into webs that differ with respect to one of theirextension length and their curve section.
 5. The brake disk according toclaim 4 wherein the webs are designed as primary webs that have amaximum extension length, secondary webs that are shorter relative tothe primary webs, and tertiary webs that are shorter relative to thesecondary webs.
 6. The brake disks according to claim 5 wherein theprimary webs extend along their curve section starting from the innerperipheral edge of the brake disk up to a preset spaced distance fromthe outer peripheral edge and thus end in front of the latter, whereinthe secondary webs are arranged along the curve section thereofapproximately in the middle between the inner and outer peripheral edgesand end in a preset spaced distance in forward the inner peripheral edgeand the outer peripheral edge, and wherein the tertiary webs extend fromthe outer peripheral edge of the brake disk starting along the curvesection thereof approximately to the middle lying between the inner andouter peripheral edges.
 7. The brake disk according to claim 5, whereinfive webs that consist of secondary webs and tertiary webs are arrangedalternating between, two successive primary webs (16 a).
 8. The brakedisk according to claim 7 wherein a secondary webs is disposed betweensuccessive tertiary webs.
 9. The brake disk according to one of claims5, wherein each of the primary webs extends over such a curve sectionlength providing a negative and a positive curvature section relative tothe direction of rotation of the brake disk.
 10. The brake diskaccording to one of claims 5, each of the secondary webs and thetertiary webs extends over such a curve section length that the latteris curved only in one direction.
 11. The brake disk according to claims9, wherein each of the secondary and tertiary webs are curved onlypositively, and the positive curvature corresponds to a curvature thatis opposite to the direction of rotation the brake disk
 12. The brakedisk according to one of claims 9, wherein the points of inflection ofthe curvature sections of the primary webs and the radial inner ends ofthe secondary webs essentially lie on a common circular line around thecenter of the brake disk.
 13. The brake disk according to one of claims5, wherein the radial inner ends of the tertiary webs are extended outvia the force application radius that lies approximately in the middlein friction disks.
 14. The brake disk according to 5, wherein the radialouter ends of the secondary webs lie essentially on a circular patharound the center of the brake disk, which the radial outer ends of theprimary webs also lie, and which is situated by a preset displaceddistance from the outer peripheral edge of the brake disk.
 15. The brakedisk according to claim 5, wherein each of the primary webs on the innerperipheral edge of the brake disk and the corresponding, radial innerweb curve sections is curved with a radial inner primary web end in thedirection of rotation of the brake disk in a manner whereby such primaryweb end section with a straight line starting from the center of thebrake disk and applied through the radial inner primary web end as atangential beam includes an angle in the range of 0 and 20 degrees. 16.The brake disk according to claim 5, wherein each of the tertiary websthat is extensive up to the outer peripheral edge of the brake disk andthe corresponding radial outer web curve sections with a radial outertertiary web end is curved in the direction of rotation of the brakedisk in a manner whereby such tertiary web end section with a straightline that starts from the center of the brake disk and is appliedthrough the radial outer tertiary web end includes, as a tangentialbeam, an angle in the range of 0 to 30 degrees.
 17. The brake diskaccording to claim 15 wherein said angle is in the range of 12 to 17degrees.
 18. The brake disk according to claim 16 wherein said angle isin the range of 10 to 22 degrees.
 19. A disk for a disk brake of avehicle, comprising: a pair of axially spaced annular disks; a set ofprimary webs circumferentially spaced relative to and interconnectingsaid disks, each disposed at least partially along an S-shaped lineintersecting inner and outer peripheral edges of said disks; a set ofsecondary webs circumferentially spaced relative to and interconnectingsaid disks, each disposed at least partially along an S-shaped linedisposed substantially parallel to said first mentioned S-shaped lineand intersecting said inner and outer peripheral edges of said disks;and a set of tertiary webs circumferentially spaced relative to andinterconnecting said disks, each disposed at least partially along anS-shaped line disposed substantially parallel to said first mentionedS-shaped line and intersecting said inner and outer peripheral edges ofsaid disks, wherein outer ends of said primary webs are spaced from saidouter peripheral edge of said disks, inner ends of said tertiary websare spaced from said inner peripheral edge of said disks, and the outerand inner ends of said secondary webs are spaced from said outer andinner peripheral edges of said disks respectively.
 20. The diskaccording to claim 19 wherein said webs are equally spacedcircumferentially.
 21. The disk according to claim 19 wherein three ofsaid of tertiary webs are disposed between a successive pair of primarywebs and a secondary web is disposed between each successive pair oftertiary webs.
 22. The disk according to claim 19 wherein outer portionsof said S-Shaped lines curve in the direction of rotation of said disk.23. The disk according to claim 19 wherein inner portion of saidS-shaped lines are angularly displaced from a radius of said disk in therange of 0 to 20 degrees.
 24. The disk according to claim 19 whereinouter portion of said S-shaped lines are angularly displaced from aradius of said disk in the range of 0 to 30 degrees.